Electrically-operated toothbrush



Jan. 28, 1964 M. A. FREsARD 3,119,135

ELECTRICALLY-OPERATED TOOTHBRUSH Filed Nov. 14, 1961 I @II- INVENTOR Marcgl Alexis Fre'sard 4 a... 2,.1 L

ATTQRNEYS United States Patent 3,119,135 ELECTRKCALLY-OPERATEDTOOTHBRUSH Marcel Aiexis Frsard, Geneva, witzeriaud, assiguor toEtabnssement Aesup, Vaduz, Liechtenstein, a firm of Liechtenstein FiiedNov. 14, 1961, Ser. No. 152,345 Claims priority, appiieation SwitzerlandNov. 21, 1969 6 Ciairns. (Ci. 15-22) This invention relates toelectrically-operated toothbrushes, and particularly to a hygienicwatertight arrangement therefor.

Electrically-operated toothbrushes are now known including a casingforming a handle, a shaft extending through the front end of the casingfor carrying a toothbrush head, and electrical means mounted within thecasing for oscillating the shaft.

One particular type is disclosed in US. Patent 2,917,758, issuedDecember 22, 1959, to Held et al. In this toothbrush the shaft isrotationally oscillated so as to impart a corresponding motion to atoothbrush head attached thereto and brush the teeth in the lengthwisedirection thereof. Other types are known in which a longitudinaloscillation is imparted to the shaft.

In an electrically-operated toothbrush, it is important to prevent theentry of water or other liquid into the portion of the casing containingthe electrical driving means, both because of the corrosive effects ofthe water and the danger of electric shock. Watertightness isparticularly important when the toothbrush is energized from the powermains where the line voltage can be dangerous.

With an oscillating shaft it is difficult to achieve watertightness,While at the same time permitting oscillations of sufficient amplitudeto be obtained with the limited power available. Thus, a watertightbearing between the shaft and the front end of the casing has been foundinsufficient to maintain Watertightness over an extended period of use.

To further assure watertightness it has been found desirable to employ aflexible water-impermeable partition member extending between the shaftand the casing, and secured to the shaft and casing in watertightrelationship. Due to the flexibility of the partition member, it may bedeformed during operation and oscillations are not unduly impaired. Inparticular, with the rotationally oscillating brush of the aforesaidpatent, it has been found advantageous to employ a sleeve of flexiblewater-impermeable material which encircles the shaft and extendstherealong a substantial distance. The sleeve is flared, with itssmaller diameter front end (toward the end of the casing where the shaftprotrudes) secured tightly around the shaft, and its larger diameterrear end secured in watertight relationship with the inside of thecasing.

US. Patent No. 3,060,474, issued October 30, 1962, to Woog discloses anarrangement of this type.

It is desirable to have the flexible partition member mounted inside thecasing to afford protection against accidental damage. However, evenwith a reasonably watertight bearing between the shaft and the front endof the casing it has been found that water, toothpaste, saliva, etc.commonly present during normal use penetrate into the front end of thecasing. The elastic partition or sleeve prevents the water mixture fromreaching the elec- "ice 2 trical elements. However, bacterial action,etc, is likely to develop, resulting in an unhygienic and mustycondition.

In accordance with the present invention, the flexible partition memberor sleeve is employed to prevent entry of water, etc. into theelectrical portion of the casing, and is mounted inside the casing atthe front end thereof so that it cannot easily be damaged, as abovedescribed. Then, apertures are provided in the front end of the casingto enable washing of the interior thereof.

Advantageously apertures are formed in the side wall of the frontportion of the casing, and preferably on opposite sides of the shaft,together with one or more apertures at the front end of the casingadjacent the shaft. This permits a stream of water to flow through thechamber between the front end of the casing and the partition member, soas to wash out any accumulation of toothpaste, etc. In the specificembodiment described hereinafter, a plurality of apertures are employedadjacent the shaft, and the portions of the casing between the aperturesform bearing surfaces which limit lateral displacement of the shaft.

The invention will be more fully understood from the followingdescription of specific embodiments thereof, taken in conjunction withthe drawings, in which:

FIG. 1 is an overall view of the toothbrush including handle andattached stem-brush;

FIG. 2 shows a portion of the handle partly in crosssection;

FIG. 3 is a view of the thereof; and

FIG. 4 illustrates a modification.

Referring to FIG. 1, a casing 10 forms a handle, and shaft 11 projectsfrom the front end thereof. In this embodimentt the brush head isdetachable from the handle, and comprises a stem 12 with bristles 13mounted thereon, with a coupling at 14 enabling the brush-stem to beconveniently attached and removed. The coupling may be of the typedescribed in application Serial No. 103,482, filed April 17, 1961, byMoret, for Toothbrush Attachment.

Inside casing 10 is electrical means for oscillating shaft 11, generallyindicated by dotted box 15, and in this particular embodiment is a motorof the type shown in the aforesaid Patent 2,917,758. Resilient areas 16,16 are provided for actuating an internal switch or other mechanism forcontrolling oscillation of the shaft. Details of these components arenot shown since they form no part of the present invention.

Referring to FIG. 2, a sleeve 21 of flexible, waterirnpermeable materialsuch as neoprene is secured at its front end 22 to an enlarged section11' of shaft 11. The unstretched diameter of front end 22 may be madesmaller than the diameter of shaft portion 11' so that its elasticityproduces a tight fit and insures watertightness. The portion 11 of theshaft may be somewhat larger so as to provide an abutment for end 22 ofthe sleeve. Additional means for insuring a watertight connection may beemployed if desired.

The rearward end 23 of sleeve 21 is held tightly against the inside ofcasing 10 by a ring 24. Thus, the sleeve 21 prevents .any entry of waterto the rearward portion of the casing 10 where the motor and anyelectric circuit components are located. In operation the front end 22twists with respect to rear end 23, the flexibility of the handle fromthe front end sleeve allowing this action to take place withoutimpairing the watertight connections with shaft and casing.

The rearward portion of the casing is constructed so as to bewatertight. To this end casing is advantageously made in one piece withresilient areas 16, 16' either integral with the casing or firmlyadhered thereto. An insulating plastic is preferred for the casingmaterial. In order to permit assembly, a cap 10 of the casing is formedseparately and then made integral with the main body of the casing, asby fusing. Electric power is supplied to the toothbrush throughconductors and a molded plastic section 26 is provided to insurewatertightness at the point where conductors 25 enter casing 10.

A plurality of small apertures 31 are provided in the sidewall of thefront portion of the casing, and a like plurality of apertures areformed in the side wall on the opposite side of the shaft, as indicatedat 31' in FIG. 2. Also, in order to allow free flow of water through thefront section of the casing, a plurality of apertures 33 are provided inthe front end of the casing, as shown in FIG. 3. These are adjacent theshaft, and the portions 34 of the casing between the apertures 33closely approach the shaft and form bearing surfaces which limit lateraldisplacement of the shaft.

It will be seen that with the apertures arranged as shown, the frontportion of the casing can be put into water, or passed under a watertap, in order to wash out any accumulation of toothpaste, etc. Further,when the toothbrush is not in use, the apertures allow air to enter topromote hygienic conditions.

Sleeve 21 may be circumferentially pleated as shown in FIG. 2, orunpleated, or longitudinally pleated, in order to secure adequateflexibility so as not to substantially impair oscillation of shaft 11.

FIG. 4 shows a modification employing an unpleated sleeve 35 whichextends somewhat farther along the shaft. The front end 36 is secured toshaft section 11' as described before, and the rear end 37 is tightlypressed against the inside of casing 10" by a ring 24. In this caseapertures 38 are placed somewhat farther from the front end of thecasing, but still lie between the front end and the region at which theflexible member is secured to the casing. Similar apertures may beformed on the other side of the casing, and in the end of the casingadjacent the shaft, as described in connection with FIG. 2.

I claim:

1. An electrically-operated toothbrush which comprises (a) an elongatedcasing forming a handle,

(b) a shaft extending through the front end of the casing for carrying atoothbrush head,

(0) electrical means mounted within the casing for oscillating theshaft,

(d) a flexible water-impermeable partition member inside the casingextending between the shaft and the casing and secured to the shaft andcasing in watertight relationship,

(2) the flexible partition member being secured to the inside of thecasing at a region spaced from the front end of the casing,

(f) the portion of the casing rearward of the flexible partition memberbeing watertight and said electrical means being mounted therein,

(g) at least one aperture in the sidewall of the front portion of thecasing ahead of the flexible partition member and at least one aperturein the front end of the casing adjacent the shaft for enabling washingof the interior of the front portion of the casing up to the flexiblemember by a flow of water therethrough.

2. An electrically-operated toothbrush in accordance with claim 1including a plurality of apertures in the front end of the casingadjacent the shaft, the portions of the casing between the aperturesforming bearing surfaces limiting lateral displacement of the shaft.

3. An electrically-operated toothbrush comprising (a) an elongatedcasing forming a handle,

(b) an electric motor mounted within the handle,

(0) a shaft oscillated by the motor and extending through the front endof the casing for oscillating a toothbrush head attached thereto,

(d) a flexible sleeve of water-impermeable material encircling the shaftinside the casing and having one end secured tightly around the shaftand the other end secured in watertight relationship with the inside ofthe casing at a region spaced from said front end of the casing forpreventing entry of water to the portion of the casing rearward of thesleeve while allowing oscillation of the shaft,

(e) the portion of the casing rearward of the sleeve being watertightand said electric motor being mounted therein,

(f) at least one aperture in the sidewall of the casing between thefront end of the casing and the region at which the flexible sleeve issecured to the casing and at least one aperture in the front end of thecasing adjacent the shaft for enabling washing of the interior of thefront portion of the casing up to the flexible member by a flow of watertherethrough.

4. An electrically-operated toothbrush in accordance with claim 3 inwhich the front end of the casing closely approaches the shaft, andincluding (a) a plurality of apertures in the sidewall of the frontportion of the casing ahead of the flexible sleeve and on opposite sidesof the shaft,

([1) and a plurality of apertures in the front end of the casingadjacent the shaft,

(0) the portions of the front end of the casing between thecorresponding apertures forming bearing surfaces limiting lateraldisplacement of the shaft.

5. An electrically-operated toothbrush comprising:

(a) an elongated casing forming a handle,

(b) an electric motor mounted within the handle,

(c) a shaft rotationally oscillated by the motor and extending throughthe front end of the casing for rotationally oscillating a toothbrushhead attached thereto,

(d) the front end of the casing closely approaching the shaft,

(e) a flexible sleeve of water-impermeable material encircling the shaftinside the casing and extending therealong a substantial distance,

(f) the front end of the sleeve being secured tightly around the shaftand the rear end thereof being secured in watertight relationship withthe inside of the casing to prevent entry of water to the portion of thecasing rearward of the sleeve while allowing rotational oscillation ofthe shaft,

(g) the portion of the casing rearward of the sleeve being watertightand said electric motor being; mounted therein, I

(h) a plurality of apertures in the sidewall of the front portion of thecasing ahead of the flexible sleett and on opposite sides of the shaftand a plurality of aper-' tures in the front end of the casing adjacentthe shaft for enabling washing of the interior of the front portion ofthe casing up to the flexible sleeve by a flow of water therethrough,

(z') the portions of the front end of the casing between thecorresponding apertures forming bearing surfaces limiting lateraldisplacement of the shaft.

6. An electrically-operated toothbrush which comprises (a) an elongatedcasing forming a handle,

(b) a shaft extending from the interior of the casing at the front endthereof for carrying a toothbrush head,

(0) electrical means mounted Within the casing for oscillating theshaft,

(d) a flexible water-impermeable partition member inside the casingextending between the shaft and the casing and engaging the shaft andcasing in substantially watertight relationship,

(e) the flexible partition member engaging the inside of the casing at aregion spaced from the front end of the casing,

(f) said electrical means being mounted in the casing rearward of saidflexible partition member,

(g) at least one aperture in the side wall of the front portion of thecasing ahead of the flexible partition member and at least one aperturein the front end of the casing adjacent the shaft for enabling Washingof the interior of the front portion of the casing up to the flexiblemember by a flow of Water therethrough.

References Cited in the file of this patent UNITED STATES PATENTSBanning July 2, Sticht June 23, Shand et a1 Aug. 29, Smithson Oct. 27,Held et a1 Dec. 22, Wepfer July 31,

FOREIGN PATENTS Great Britain May 11,

1. AN ELECTRICALLY-OPERATED TOOTHBRUSH WHICH COMPRISES (A) AN ELONGATEDCASING FORMING A HANDLE, (B) A SHAFT EXTENDING THROUGH THE FRONT END OFTHE CASING FOR CARRYING A TOOTHBRUSH HEAD, (C) ELECTRICAL MEANS MOUNTEDWITHIN THE CASING FOR OSCILLATING THE SHAFT, (D) A FLEXIBLEWATER-IMPERMEABLE PARTITION MEMBER INSIDE THE CASING EXTENDING BETWEENTHE SHAFT AND THE CASING AND SECURED TO THE SHAFT AND CASING INWATERTIGHT RELATIONSHIP, (E) THE FLEXIBLE PARTITION MEMBER BEING SECUREDTO THE INSIDE OF THE CASING AT A REGION SPACED FROM THE FRONT END OF THECASING, (F) THE PORTION OF THE CASING REARWARD OF THE FLEXIBLE PARTITIONMEMBER BEING WATERTIGHT AND SAID ELECTRICAL MEANS BEING MOUNTED THEREIN,(G) AT LEAST ONE APERTURE IN THE SIDEWALL OF THE FRONT PORTION OF THECASING AHEAD OF THE FLEXIBLE PARTITION MEMBER AND AT LEAST ONE APERTUREIN THE FRONT END OF THE CASING ADJACENT THE SHAFT FOR ENABLING WASHINGOF THE INTERIOR OF THE FRONT PORTION OF THE CASING UP TO THE FLEXIBLEMEMBER BY A FLOW OF WATER THERETHROUGH.